Exams › JEE Main › Chemistry
For the reaction C2H5OH(l) + 3O2(g) → 2CO2(g) + 3H2O(l) at 27 °C, the enthalpy change is −1366.5 kJ mol−1. What is the corresponding internal energy change at this temperature?
- −1369.0 kJ
- −1364.0 kJ
- −1361.5 kJ
- −1371.5 kJ
Correct answer: −1361.5 kJ
Solution
The internal energy change can be calculated from the enthalpy change by accounting for the work done by the system during the reaction, which is related to the change in the number of moles of gas. In this case, the reaction produces fewer moles of gas than it consumes, leading to a decrease in internal energy that is reflected in the correct option.
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